ZIP 94505 falls in Contra Costa County, California. We have not measured septic data for this county yet. The county page below has what we do know: where records are kept and whether the portal is public.
ZCTA 94505 is not entirely inside one county. Land-area share is from the 2020 Census ZCTA-to-county relationship file.
| County | Land in this ZIP | Documents held | On septic (county) | On sewer (county) |
|---|---|---|---|---|
| Contra Costa County, California | 96% | — | — | — |
| Alameda County, California | 4% | — | — | — |
| San Joaquin County, California | 0% | — | — | — |
1 businesses on record with an address in this ZIP: pumping, installation, design, inspection and repair. Not an endorsement, and we take no fee.
| Company | City | Phone | Rating |
|---|---|---|---|
| Diablo Excavation & Construction | Discovery Bay | (925) 628-8877 | — |
Land-area overlap is from the 2020 Census Bureau ZCTA5-to-county relationship file, not an estimate of ours. Parcel and document counts are rows we hold, not a survey of every property in the ZIP. Last verified 2026-09-01.
We have not measured septic-versus-sewer status for this county yet.
ZIP 94505 spans 3 counties: Contra Costa County, California, Alameda County, California, San Joaquin County, California.